New derivatives of esters of n-substituted alpha-amino acids



United States Patent 3,513,187 NEW DERIVATIVES 0F ESTERS 0F N-SUBSTI- TUTED ALPHA-AMINO ACIDS Paul Viennois, Lyon, France, assignor to Laboratoires Novalis, Oullins, Rhone, France, a French company No Drawing. Filed Aug. 10, 1964, Ser. No. 388,711 Claims priority, application Great Britain, Aug. 3, 1%3, 31,896/ 63 Int. Cl. C07c 101/104, 103/28 US. Cl. 260--471 3 Claims 10 ABSTRACT OF THE DISCLOSURE Compounds of formula COY in Which R is an alkyl having at most three carbon atoms or a phenyl, R is a phenyl, or a p-chlorophenyl, or R and R together form a five or a six member ring, Y is --OR or --NH or The present invention relates to the derivative products of esters of N-substituted alpha-amino-acids, corresponding to the following general formula:

R1 COY 112 NHC OX in which: R is an alkyl radical having at most 3 atoms of carbon, or the phenyl radical; R is the phenyl radical, or phenyl substituted in para by a chlorine atom; or alternatively, R and R may form together a pentagonal or 3,513,187 Patented May 19, 1970 hexagonal cycle with the carbon atom in alpha; Y is -OR or --NH or R R or R being an alkyl radical having at most 4 atoms of carbon, and n being equal to 2 or 3; and X is NHR or R or the trimethoxy-phenyl radical, R representing an atom of hydrogen or the phenyl radical and R being an alkyl radical with l to 3 atoms of carbon inclusive.

The present invention also relates to the pharmaceutical compositions containing one of the compounds according to the invention, associated with acceptable and nontoxic pharmaceutical bases, these compounds being especially useful by reason of their central depressive activity, due to their extremely loW toxicity (they have been tried out in doses of 50 and 100 mg./kg. with complete harmlessness).

The present invention further relates to a method of preparation of the compounds specified above.

This method consists:

(a) In synthesizing hydantoins having the formula:

by condensation of the corresponding ketone with a sodium cyanide and ammonium carbonate;

(b) In hydrolyzing the hydantoins obtained by barytawater or by soda to amino-acids (efficiency of the order of about having the formula:

R1 COOH (c) In esterifying the amino-acids formed by heating to reflux in a quantity of an anhydrous alcohol R OH saturated With gaseous hydrochloric acid, so as to form the esters (efiiciency of the order of 52 to 83%):

N Hz (III) in the form of hydrochloride;

3 (d) Either in converting the esters obtained by the action of potassium cyanate or phenyl isocyanate to ureide derivatives having the formula:

(d') Or in converting the esters obtained by an anhydride of carboxylic acid or of an acid chloride to N- acylated derivatives (efficiency of the order of 90 to 100%) having the formula:

R COOH X z NHCORs R (VI) followed by dehydration by heating to reflux in acetic anhydride to azlactones (efliciency of about 80%):

C Ra N=C R (VII) which is treated with concentrated ammonia so as to give the amides (efliciency from 50 to 60%) R1 CONH Ra NHCORs (VIII') EXAMPLE 1 Ethyl-5 phenyl-5 hydantoin: (Formula I, in which 1= 2 5; 2= e 5)- 67 grams of propiophenone (0.5 mol.) in 700 m1. of ethyl alcohol, 50 grams of sodium cyanide (more than 1 mol.) in 100 ml. of water, and 200 grams of ammonium carbonate (more than 2 mols.) in 500 ml. of water, are heated in a water-bath to 60 C. for 3 hours. After having allowed the temperature of the bath to increase to 80 C., the solution is filtered and then concentrated under vacuum until precipitation begins, and finally it is cooled. The hydantoin precipitated is filtered and dried and then re-crystallized in a mixture of alcohol and water.

4 Efiiciency: 60.3 grams (60%); Melting point: 200- 204 C.

EXAMPLE 2 Amino-2 phenyl-2 butyric acid (Formula II in which R1=C2H5 and R2=C3H5).

97.5 grams of hydantoin obtained in Example 1 (0.48 mol.) dissolved in a solution of 455 grams of barium hydroxide (1.44 mol.) in 1160 ml. of water are heated for 18 hours at a pressure of 250 mm. of mercury. After filtration while hot, the filtrate is neutralized with sulphuric acid, the barium sulphate formed is eliminated, and the solution is concentrated under vacuum until precipitation begins.

Efiiciency in filtered and dried acid=46 grams; Melting point-=240 C.

The mother liquors, after evaporation under vacuum still yield 10 grams of acid containing impurities and mineral salts.

EXAMPLE 3 Amino-2 phenyl-2 ethyl butyrate (Formula III in which 1= z 5; 2= e 5 a= 2 5)- 28 grams of acid obtained in Example 2 in 560 ml. of absolute ethyl alcohol saturated with dry acid are heated to reflux for 4 hours.

The residue obtained after evaporating-off the excess alcohol and hydrochloric acid is treated with the minimum quantity of water. The free ester is extracted from the aqueous solution, neutralized with sodium bicarbonate in ether, which is then evaporated.

Efficiency=22 grams (68%); Index of refraction at 21 C.: n =1.5055.

EXAMPLE 4 Ureide-Z phenyl-2 ethyl butyrate (Formula IV in which 1= 2 5; 2= s 5; 3= 2 s; 4=

3.5 grams of ester obtained in Example 3 in 75 ml. of chloroform, 9.4 grams of potassium cyanate and 4.5 grams of pure acetic acid are stirred for 3 hours at the ambient temperature. The solution is then filtered and evaporated under vacuum. The residue treated with 25 ml. of water gives 3.5 grams of ureide derivative collected by filtration.

Melting point=176 C. (after re-crystallization in alcohol).

EXAMPLE 5 Phenyl ureide-2 phenyl-2 ethyl butyrate (Formula IV in R1=C2H5; R2=C6H5; R3'=C2H5 and R4==C6H5).

To 2.5 grams of ester (0.0121 mol.) obtained in Example 3 in 30 ml. of ether, there are added 1.58 grams of phenyl isocyanate. The reaction is exothermic and from the ether 3.2 grams of product are rapidly precipitated.

Melting point=180-182 C. (After re-crystallization in a mixture of alcohol and water).

EXAMPLE 6 Acetamido-Z phenyl 2 ethyl butyrate (Formula V in R1=C2H5; R2=C6H5; R3=C2H5 and R5=CH3).

To 10 grams of ester (0.0483 mol.) obtained in Example 3 in 50 ml. of benzene are added 5.4 grams of acetic anhydride (0.053 mol.). The reaction is exothermic. After cooling, the mixture is heated for one hour to reflux and then evaporated dry so as to give 11.55 grams of practically pure N-acetylated ester.

Melting point=102-104 C. (after re-crystallization in a mixture of alcohol and water).

EXAMPLE 7 Propionamide-Z phenyl-2 ethyl butyrate (Formula V in which R =C H R =C H R =C H and R =C H 28 grams of ester obtained in Example 3, and 19 grams of propionic anhydride are heated for one hour to reflux in 140 ml. of benzene. When the benzene has been evaporated, the residual oil poured into water crystallizes so as to give 33 grams (93%) of N-acylated crude ester.

Melting point=7680 C. (after re-crystallization in the benzene-hexane mixture).

EXAMPLE 8 6 Calculated (percent): C, 66.38; H, 7.23; N, 5.96. Found (percent): C, 66.46; H, 7.46; N,6.l5.

EXAMPLE 9 Diethyl-Z, 4 phenyl-4 oxazoline-Z one-5 (azlactone).

13.1 grams of propionamido-Z phenyl-Z butyric acid obtained in Example 8 are heated for 25 minutes to reflux in 32 ml. of acetic anhydride. The latter is evaporated under vacuum and the yellow oil obtained is distilled.

Boiling point:146147 C. at 12 mm. of mercury; n =1.5095; efliciency:9.6 grams (79%);

Calculated (percent): N, 6.45. Found (percent): 6.63.

EXAMPLE 10 Propionamide-Z phenyl-Z butyramide.

3.25 grams of azlactone obtained in Example 9 in ml. of ether and 45 ml. of concentrated technical ammonia are stirred for one hour. After evaporation of the ether and the ammonia, the White product obtained crystallizes in brilliant flakes in the benzene.

Melting point: 142 C.; efiiciency=1.83 grams (54% By following the process described in the preceding examples, there have also been prepared the compounds referred to in Tables 'I, I I and III which follow below. The operating conditions (re-crystallizing solvent), the melting points and the analyses of these compounds are also given in the tables referred to.

TABLE I R1 C O 0 R R2 NHCONHRz (IV) I Analysis 0 Percent; H Percent N Percent Calcu- Calcu- Calcu- Com- Recrystallated Found Iated Found lated Found pound Empirical Melting lisation No. R1 R2 R3 R4 formulae point, C. solvent 0 T C T C '1 oLn-om- 1V1 C C0115 CusHzoNzOs Alcohol CH2CHg CH2CHz- 1V2. C4119 H C11H20N20: 102 d0 57. 89 57. 47 3. 77 8. 83 12. 28

CH2GH2- CHa-C'Hz- IV3 C4119 C0115 C 7H24N2Oa 174176 Alcohol-Water". 67. 11 66. 93 7. 89 7. 74 89. 21 9. 23

CH2-CH (KHz-CH2- IV4 CH2 C2115 H CmHreNzOa 153 Alcohol (EHrCHr- (BLIP-CH2- 1V5 (3H2 C2115 C2115 MH22N2O3 174-176 Alcohol-water.-- 66. 24 66. 42 7. 59 7. 49 9. 66 9. 81

CH2 CH2 GE -CH2- IVu- CH2 C4015 H C12H22N20a 122 Alcohol 59. 50 59. 30 9. 09 9. 15 11. 6 11. 72

CH2'CH2 IV7 CH3 CeHs CzHa CsHs 012112411203 -172 Alcohol water 9. 05 C CsHs 041210 H Cr4H2oN2Os 128 lcohol 10. 74

5115 C4He CaHa zoHerNzOa ClCuH4 C 115 H CrzHrsClNzOg C5115 C4119 H CtaHrsHzOa C6115 C2115 C6115 C1 H22N2O3 -182 do C0115 04H CaH5 CzrHgsNaOa 140 Alcohol-water.-- 71. 19 71. 22 7. 34 7. 41 7. 91 7. 95

TABLE III R1 CONE;

Ra NHCORa (VIII) Analysis Melting Recrystal- C Percent H Percent N Percent Compound point, lisation No. R1 R2 R Name C. solvent. Cale. Found Cale. Found Cale. Found CH2CH2 VIII; J} CH3 Aeetemide-1-cyclo 219 Ethanol.

Hg-CHgpentane earbemide.

CH CH VIII H3 CH3 Acetamided cyelo- 181 Etenol, 50%-... 58. 69 58. 74 8.69 8. 65 15.22 15.19

I hexane earbamide. CHzCHz VIIIa OQHfi CEHE CH3 AIgettamideigphenyI-Z 177 Ethanol, 50%.-- 65.45 65.63 7.28 7.18 12.73 12.84

u yram e. VIII C2HE C 13 C2115 Priopionamide-Z- 142 Benzene 66.66 66.75 7.69 7.75 11.97 11.82

plignyla butyram e. V111 0H 0.111 C2H5 Propionamide-Z- 157-158 Ethanol, 65.45 65.79 7. 28 7. 38

pheilyl-2propionam e.

The following intermediate compounds obtained during the preparation of the final products referred to in Tables I, II and III, are also new.

(2) Action on the position reflexes This test is based on the time during which mice can hold themselves on a wooden rod of 20 mm. in diameter TABLE IV R: /OOOH R2 NH2 (11) Melting Empirical point, Recrystalliza- R1 R2 formula 0. tion solvent i ifl fi jil CH 01mm- CqHmclNOz 260 Wateralcohol.

TABLE v rotating on its axis at a slow speed. This standard test has R O 0 0R been employed in the study of tranquilisers (see Kinnard 3 (W. 1. Carr 0. J.)-J.P.E.T.1957, 121, 354). Pull-up test.-This test consists in suspending mice by R2 NH; (III) the front feet from a metal wire stretched horizontally. It is assumed that there is a sedative effect when the Refractive animal is not able within five seconds to make a recovery E i 1 de ggxflpound 1 R2 R3 101E118? un; which brings on the wire one and sometunes both hlnd 1H1 CHFCHPCHF 04m CnHnNOz M5030 feet (see Courvoisler (S) J.C11n. Exp. Psychopath. 1956,

17, 25). H2-CH2- (3) Potentiahzatlon of the hypnotlc activity of nembutal 8 5 11 8i? l bl O N b 1 d h 1 f 1 a 4 a w 12 2 em uta is injecte in a omogeneous se ection 0 25 I I Z E ggggbi {262221 mlce at a very small dose which does not induce. sleep CaHa i e CHH21NO3 149502 (20 mg./kg.). The test is positive when the prior administration (15 to 30 minutes) of the product to be tested permits this threshold dose of nembutal to induce sleep, the intensity and the duration of which are a functio not the activity of the compound studied (see Boissier PHARMACOLOGICAL TESTS 5 The central depressive activity of the ureide compounds (Formula IV) and of the N-acylated compounds (Formula V) according to the invention, has been determined by the following tests:

(1) Action on spontaneous motory activity (I. R.) Actualites pharmacol. 1959, 12, 1).

(4) Inhibition of the Straub phenomenon (antimorphinic activity) Known by the name of the Straub phenomenon, the catatonus of the tail, observed in mice treated with morphine (20 mg./kg.) is inhibited by certain tranquillisers (Behactyzine") and compounds having an anticholinergic activity (see Boissier (J. R.) Therapie 1958, 13, 1074).

This test is also included in the screening tests adopted.

The results of these tests are given in Table VI below: From this it is deduced that the dose used for the test TABLE VI Actography Potentiall- Inhibition Trembling Rotating Pulling zation oi oi Straub cages rod test test Nembutal phenomenon Compo IV 0 IV 0 V 0 0 V 0 0 0 V 0 V l 0 V l V o 0 V I 0 0 o v o 0 0 v 14.-.- 0 0 V 16.... 0 0 v 17.--- 0 o 0 0 VIII 3-..- 0 VIII 4 Central depressive activity of derivatives tested. represents an activity oi the order oi l'fith oi that of the chloro-promezine used as a standard.

These comparative results show that a central activity corresponds substantially to the 50 per 100 effective dose can be clearly shown by means of the tests made with (ED under these experimental conditions. the ethyl esters of N-acylated amino-acids.

The effect is a maximum for the derivative N0. V 8: i g test! propionamide-2 phenyl-Z ethyl butyrate.

The elongation of the main chain (ethyl valerates Nos. Duration oitest; V 15 and V 16), of the N-acylated chain (butyramide-2, 15m1n8 mm 60 mins. 120 mm trimethoxy-benzamide-Z, derivatives Nos. V 9, V 10 and V 11) or of the esterifying group (butyl esters, derivalfifii iugil 3+ 4-8 (H9 64 tives Nos. V l and V 2) has the effect of causing a definite reduction of the activity. 30

The replacement of the ester function by a primary amide function (-CONH is also not advantageous: the derivatives VIII 3 and VIII 4 have a diminished ac- It can be concluded that the dose used for the test (100 mg/kg. per bone) corresponds substantially to the 50 per 100 effective dose (ED under these experimental tivity as compared with that of the corresponding ethyl condltlons' esters, and especially have a shorter period of action. Potentialization of Nembutal:

Duration of test 30 mins. mins. 60 mins. 120 mins.

Number of mice drugged Cgmparison group (10 mice) nembutal 20 mg.lkg. 1 0 0 o Treairi' 'rb'dfi'iib'ifiii 65111551135 'V'ii; Treated group (10 mice) Compound No. V 8; 100

mgJkg. per bone, 30 min. before the uembutaL. 8 6 5 1 Treated group (10 mice) Comp V 8; 100 mg./kg.

per bone, 60 min. before the N embutal 10 9 9 6 Treated group (10 mice) Comp V 8; mg./kg.

per bone, min. before the nembutal 6 5 2 2 The results obtained with propionamide-Z phenyl-Z These results show that in this test, the ED is 50 ethyl butyrate (No. V 8) are given below: mg./kg. for mice.

Acute general toxicity-Administered by the mouth in Investigation of secondary eifects-When administered mice (gastric intubation) at a dose of 1.0 g/kg., this com 50 by intravenous injection on a dog with a destroyed medulla, pound possesses complete harmlessness. No mortality was propionamide-Z ethyl butyrate (10 mg./ kg.) has proved to observed on a group of 10 mice in the 8 days following have no activity on the blood pressure and the breathing. this administration. Therapeutic application-The derivatives referred to In the 24 hours following the administration of such a above can be employed for the treatment of illnesses redose by the mouth, the mice treated behaved in an appar- 55 sulting from the attack on the central nervous system (exently normal manner. cessive nervous excitability, characteristic instability, in-

Actography (mice), somnia, etc.).

They can be administered alone or in association with NUMBER OF lgg gf 0N other active principles, by the mouth (pills, tablets, sugar- 0 coated tablets) or by rectal administration.

The posology is of the order of 100 mg. per dose, at the Treated ro p rate of 2 to 10 doses per 24 hours. gjgfi g ififig What I claim is:

1. A compound of formula:

[Average of 10 tests] One hour before test 4, 300 4, 100 30 minutes aiter dosing. 3, 900 310 minutes after dosin 3, 500 5 R C DY 150 minutes after dosing. 4, 700 2, 1 210 minutes after dosing. 4, 200 1,800 270 minutes after dosing.-. 3, 400 3, 100

R N HG OX Rota rod test: 70

Dmmmmst in 11 lk 1 d 1h t t3 r r b f 1 IS an a y ra lea avmg a mos 3 01118 0 car on,

15 mins. 45 mins. mins. or the p y radical;

Comparison group (10 mice) 0 0 0 is n Treated group (10 mice) 3+ 6+ 5+ R the phe yl radical, or phenyl substituted in para 75 by a chlorine atom;

13 14 Y is #011; or v--NH, or References Cited UNITED STATES PATENTS o-(CIDM-N 2,642,459 12/ 1948 White 260-534 5 2,663,713 3/1952 White 260-534 R5, R or R being an alkyl radicalhaving at most 4 2,971,021 9/1961 Schipper 260-468 atoms, of carbon, and n being equal to 2 or 3; ,6 7 9/ 1 A l t al- 2 046 and X isNHR; or R or the trimethoxy-phenyl radical 3,344,023 9/1967 Reinhold et a] 16765 R representing an atom of hydrogen or the phenyl radical, and R being an alkyl radical with 1 to 3 10 OTHER REFERENCES atoms of carbon inclusive. 2. A compound according to claim 1 of formula ff g f figf chemlstry Heath Boston fcoQRr Noller, C. R. Chemistry of Organic Compounds; W. B.

m Saunders, Philadelphia, Pa., 1951 p. 635. LORRAINE A. WEINBERGER, Primary Examiner wherein R R,, R, and R are as therein defined.

3. The compound according to claim 2 of formula no US. (:1. X.R.

P. I. KILLOS, Assistant Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION fluent No 3 513, 187 Dated May 19, 1970 mve fl Paul Viennois It is certified that er ror appears in the above-identified patent no that said Letters Patent are hereby corrected as shown below:

Column 1, line 7, the priority date "Aug. 3, 1963,"

should read Aug. 13, 1963,

(SEAL) 1mm:

aawudu mm: 1'. sum. m.

0mm fioumissioner of Patents 

